Electronic supplementary material

Abstract

Three kinds of devices based on single Er-doped CdSe nanobelt (Er-CdSe NB), single CdSe NB and four CdSe NBs in parallel were constructed by hard mask assisted with 10-μm tungsten wire in diameter. The photoelectronic properties of three kinds of devices were investigated. It is found that the dark currents of Er-CdSe NB and CdSe NB (four CdSe NBs in parallel) are 4 × 10−10 and 1.0 × 10−13 A (8.92 × 10−11 A). They have high Ion/Ioff ratios with 2.21 × 104 and 8.97 × 105 (4.61 × 104), respectively. The corresponding responsivity, external quantum efficiency and detectivity of Er-CdSe NB and CdSe NB (four CdSe NBs in parallel) are 2.17 × 103, 3.87 × 105 and 2.27 × 1012 A/W; 3.84, 692 and 2.9 × 1011; 1.59 × 102, 2.86 × 104 and 4.96 × 1011 Jones. The responsivity Rλ and external quantum η of four CdSe NBs in parallel are higher by two orders of magnitude than that of single CdSe NB device. The detectivity D* of the former is twofold higher than that of the latter. In the meantime, Rλ, η and D* of Er-CdSe NB are 10-fold higher than those of four CdSe NBs in parallel. The superior performance of the Er-CdS NB device offers an avenue to develop highly sensitive photodetector applications.